body {
  display: flex;
  /* 主轴为垂直方向，起点在上沿 */
  flex-direction: column;
}
.top {
  height: 50px;
  line-height: 50px;
}
.top .icon-arr-right {
  font-size: 20px;
  margin-left: 10px;
}
.con {
  flex: 1;
  overflow-y: scroll;
}
